This application is based upon and claims the benefit of priority of Japanese Patent Application No. 2001-126518, filed on Apr. 24, 2001, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a blower for blowing air within a vehicle passenger compartment, and more specifically, it relates to a blower for an air conditioner and heater arrangement.
2. Description of Related Art
A blower adopted in an air conditioner for a vehicle is required to be small in size and have a large air blowing capacity. Because of this, there usually is a centrifugal fan in which gas passes radially through an impeller (see JIS B 0132 No. 1004).
In a centrifugal fan (hereinafter referred to simply as xe2x80x9cfanxe2x80x9d), a fan is received within such a scroll casing (simply xe2x80x9ccasingxe2x80x9d hereinafter) which is designed to gradually increase in cross-sectional area of passage from a start-of-winding position toward an end-of-winding position. However, since air (a main flow of air) blown from the fan is offset to a side opposite to a suction port, there is proposed a casing wherein the side (electric motor side) opposite to the suction port is enlarged in a spiral fashion so as to project to a greater extent gradually from a start-of-winding position toward an end-of-winding position.
In the casing thus proposed, however, since the shape of the suction port side and that of the electric motor side are markedly different from each other, it is difficult to use a blower (casing) in common for both blowers (casings) to be disposed on the left- and right-hand sides, respectively, of a vehicle.
On the other hand, if the size (cross section) of a casing portion parallel to an axis of rotation is made constant and the projecting portion on the side opposite to the suction port is omitted, it is necessary to make the diameter of the casing large (to an extent (angle) that the air passage is enlarged in a logarithmic spiral). This must be done in order to ensure a required cross-sectional area of air passage.
The present invention has been accomplished in view of the above-mentioned drawbacks and it is an object of the present invention to use a blower casing that is common for both blowers (casings) so that they can be disposed on the left- and right-hand sides, respectively, of a vehicle. This is accomplished while preventing the enlargement of the blower casing size.
For achieving the above-mentioned object, in a first aspect of the present invention, there is provided a blower for a vehicle, comprising a centrifugal fan which draws in air in a rotational axis direction and which blows air radially outwards, a scroll casing which houses the centrifugal fan therein and which constitutes a passage for the air to be blown from the centrifugal fan, and a drive means for rotating the centrifugal fan. The size of the scroll casing, parallel to the rotational axis direction of the scroll casing, is nearly constant from a start-of-winding position to an end-of-winding position in the scroll casing. A suction port is formed in a portion of the scroll casing corresponding to one end side along the rotational axis, while in a portion of the scroll casing corresponding to an opposite end side along the rotational axis the drive means is fixed to the scroll casing through a mounting member. A fan datum line which approximately passes through a middle part of the centrifugal fan in the rotational axis direction is offset to the suction port side with respect to a casing datum line. The casing datum line passes through an approximately middle part of the portion of the scroll casing which is parallel to the rotational axis. A flange portion of the mounting member faces the centrifugal fan and lies in a position offset to one end side of the scroll casing along the rotational axis rather than the opposite end side along the same direction.
According to this constitution, it is possible to prevent the shape of the suction port side of the scroll casing, and that of the drive means side, from becoming greatly different from each other, thus making it possible to use the scroll casing as a common casing for both blowers (scroll casings) and be disposed on the left- and right-hand sides, respectively, of the vehicle.
Further, since the fan datum line is offset to the suction port side with respect to the casing datum line and the flange portion lies in a position offset to one end of the scroll casing along the rotational axis rather than the opposite end along the same direction, there is formed a (projecting) space which is offset to the opposite end along the rotational axis direction with respect to the flange portion. Therefore, even if the size of the portion of the scroll casing parallel to the rotational axis is made nearly constant from the start-of-winding position to the end-of-winding position of the scroll casing, it is possible to ensure a sufficient cross-sectional area of air passage.
Thus, according to the above depiction, since it is not necessary to set large the diameter of the scroll casing for ensuring a sufficient cross-sectional area of air passage, it is possible to use the scroll casing for both blowers (scroll casings) to be disposed on the left- and right-sides, respectively, of the vehicle while preventing an increase in size of the scroll casing.
In a second aspect of the present invention it is preferable that the size (W) of the portion of the scroll casing parallel to the rotational axis be larger than 1.1 times and smaller than 1.6 times the size (h) of the portion of the centrifugal fan parallel to the rotational axis direction (CL). In a third aspect of the present invention, the distance (nose gap, NG) between a nose portion (No) of the scroll casing and the centrifugal fan should be smaller than 0.07 times the diameter (D) of the centrifugal fan.
If the size (W) of the portion of the scroll casing parallel to the rotational axis (CL) is enlarged, the cross-sectional area of air passage in the nose portion (No) becomes large and the flow of air becomes unstable, resulting in deterioration of the pressure and noise levels in the blower.
By setting the distance (NG) between the nose portion (No) and the centrifugal fan at the value shown in the above third aspect, it is possible to improve the blower performance and reduce the size of the scroll casing while preventing a deterioration in noise level of the blower.
In a fourth aspect of the present invention there is provided an air conditioner for a vehicle for conditioning air to be blown into a vehicle compartment, comprising an air conditioner casing, within which there flows air to be blown into the vehicle compartment, and a blower for making air flow within the air conditioner casing. The blower has a centrifugal fan which draws in air along the rotational axis and which blows air radially outwards. The blower also has a scroll casing which houses the centrifugal fan and which constitutes a passage for the air to be blown from the centrifugal fan. Additionally, there is a drive means for rotating the centrifugal fan, wherein the size (W) of a portion of the scroll casing parallel to the rotational axis (CL) is nearly constant from a start-of-winding position to an end-of-winding position in the scroll casing. A suction port is formed in a portion of the scroll casing corresponding to one end side along the rotational axis direction (CL), while in a portion of the scroll casing corresponding to an opposite end side along the rotational axis (CL) the drive means is fixed to the scroll casing through a mounting member. A fan datum line (CLf) which passes through an approximately middle part of the centrifugal fan along the rotational axis (CL) is offset to the suction port side with respect to a casing datum line (CLc) which passes through an approximately middle part of the portion of the scroll casing parallel to the rotational axis (CL). The mounting member has a flange portion which faces the centrifugal fan and lies in a position offset to one end side of the scroll casing along the rotational axis (CL) rather than the opposite end. Further, the air conditioner casing comprises common components (air inlet mode selector, heat exchanger, blow mode selector) for use common to various vehicle models and dedicated components (connection duct and scroll casing) for each individual vehicle model. The common and dedicated components being fabricated as separate components and thereafter being assembled together.
This construction representation permits easy fabrication of both air conditioner casings for right- and left-hand drive vehicles.
In a fifth aspect of the present invention there is provided a blower for a vehicle, comprising a centrifugal fan which draws in air along a rotational axis and which blows air radially outwards, a scroll casing which houses the centrifugal fan and which has a passage for air to be blown from the centrifugal fan, and a drive means for rotating the centrifugal fan. The size (W) of a portion of the scroll casing parallel to the rotational axis (CL) is nearly constant from a start-of-winding position to an end-of-winding position in the scroll casing, while first and second openings are formed, respectively, in a portion of the scroll casing corresponding to one end side of the centrifugal fan along the rotational axis (CL) and in a portion of the scroll casing corresponding to an opposite end side of the centrifugal fan along the same axis. Both openings being the same in shape, a bell mouth portion which constitutes an outer edge portion of a suction port is installed in the first opening, and the drive means is installed in the second opening through a mounting member.
According to this constitution, it is not necessary to differentiate the openings in shape with use of impression cores for manufacture which will be described later. Consequently, while attaining the reduction in mold cost for the manufacture of the scroll casing, it is possible to use the scroll casing for either blower (scroll casing) to be disposed on the left- and right-hand sides, respectively, of the vehicle.
In a sixth aspect of the present invention there is provided a method of making a scroll casing which houses a centrifugal fan and which has a first opening and a second opening formed in positions corresponding to one end side and an opposite end side, respectively, along a rotational axis of the centrifugal fan. The method entails a first impression core which forms a portion corresponding to the first opening and a second impression core which forms a portion corresponding to the second opening. The impression cores are removably mounted on a mold body and molten material is charged into the mold body in a mounted state of both impression cores to the mold body.
According to this constitution, by mere replacement of impression core it is possible to easily manufacture scroll casings for right- and left-hand drive vehicles. Consequently, it becomes possible for a scroll casing to be used for both blowers (scroll casings) to be disposed on the left- and right-hand sides, respectively, of a vehicle.
The above parenthesized numerals represent, as examples, correlations with descriptions in embodiments of the present invention. Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.